The inevitable infiltration by dampening fluid into the ink train system of lithographic printing presses is well known in the art. The presence of dampening fluid in the ink train adversely affects both image quality and color consistency. Previous attempts to eliminate dampening fluid from the ink train of lithographic printing presses have proved costly, complex, and generally involve elaborate plumbing networks which pipe air from air compressors, to air jet manifolds or nozzles which direct streams of air to impinge against inker rollers to evaporate excess dampening fluid. Typical systems are disclosed in U.S. Pat. No. 4,524,689 entitled "DEHYDRATION APPARATUS FOR PRINTING PRESS INKING SYSTEM" and U.S. Pat. No. 4,452,139 entitled "DAMPENING FLUID EVAPORATOR AND METHOD".
The use of air compressor units for delivering pressurized air to jet manifolds or nozzles within the printing press is expensive in terms of power consumption, floor space, and plumbing costs. Further, air bars and manifolds sometimes limit access to the rollers in the press. Since it is desirable to control such evaporative systems in conjunction with the operation of the ink train to prevent excessive drying of the rollers when the press is momentarily stopped or otherwise not applying ink to the printing plate through the inking rollers; compressors must be either manually turned off during periods of roller inactivity or the cost and complexity of the evaporative system must be increased further by the incorporation of automatic power or pneumatic relays.